Oils and lipids help make water-insoluble drugs soluble by dispersing them in an aqueous medium with the help of a surfactant and enabling their absorption across the gut barrier. The emergence of microemulsions (thermodynamically stable), nanoemulsions (kinetically stable), and self-emulsifying drug delivery systems added unique characteristics that make them suitable for prolonged storage and controlled release. In the 1990s, solid-phase lipids were introduced to reduce drug leakage from nanoparticles and prolong drug release. Manipulating the structure of emulsions and solid lipid nanoparticles has enabled multifunctional nanoparticles and the loading of therapeutic macromolecules such as proteins, nucleic acid, vaccines, etc. Phospholipids and surfactants with a well-defined polar head and carbon chain have been used to prepare bilayer vesicles known as liposomes and niosomes, respectively. The increasing knowledge of targeting ligands and external factors to gain control over pharmacokinetics and the ever-increasing number of synthetic lipids are expected to make lipid nanoparticles and vesicular systems a preferred choice for the encapsulation and targeted delivery of therapeutic agents. This review discusses different lipids and oil-based nanoparticulate systems for the delivery of water-insoluble drugs. The salient features of each system are highlighted, and special emphasis is given to studies that compare them.

The current study is aimed to fabricate doxorubicin (Dox) loaded mild temperature responsive liposomes (MTLs) by thin film hydration technique for enhanced in vitro and in vivo anticancer efficacy against hepatocellular carcinoma. The aforementioned Dox loaded MTLs were developed and optimized with extrusion and drug loading techniques. The optimized MTLs were in optimum size range (118.20 ± 2.81–187.13 ± 4.15 nm), colloidal stability (−13.27 ± 0.04 to −32.34 ± 0.15 mV), and enhanced entrapment of Dox (28.71 ± 2.01–79.24 ± 2.16). Furthermore, the optimized formulation (MTL1-E_(AL)) embodied improved physicochemical stability deducted by Fourier transform infra-red (FTIR) spectroscopy and mild hyperthermia-based phase transition demonstrated from differential scanning calorimetry (DSC). An in vitro drug release study revealed mild hyperthermia assisted rapid in vitro Dox release from MTLs-E_(AL) (T_100% ≈ 1 h) by Korsmeyer–Peppas model based Fickian diffusion (n < 0.45). Likewise, an in vitro cytotoxicity study and lower IC₅₀ values also symbolized mild hyperthermia (40.2 °C) based quick and improved cytotoxicity of MTL1-E_(AL) in HepG2 and MCF-7 cells than Dox. The fluorescence microscopy also represented enhanced cellular internalization of MTL1-E_(AL) at mild hyperthermia compared to the normothermia (37.2 °C). In addition, an in vivo animal study portrayed the safety, improved anticancer efficacy and healing of hepatocellular carcinoma (HCC) through MTL1-E_(AL). In brief, the Dox loaded MTLs could be utilized as safe and effective therapeutic strategy against HCC.

Applications of nanotechnology and material sciences emerge in the development of various novel drug delivery systems that have been proven as promising clinically. Among these, liposomes, noisome, polymeric carriers and lipid-based delivery system were extensively explored and enter into clinical trials and clinical applications. However, each system has its own pros and cons in term of different physicochemical, pharmacokinetics and therapeutics aspects. Lipid-polymer hybrid carriers merge the potential benefit of these structural components and can be prepared by different approaches to improve the therapeutic outcomes. In this chapter, we provide the useful insight about the lipid-polymer hybrid nanoparticles (LPHNPs) that can be prepared by using the different structural components including the synthetic and natural polymers and lipids. Among these, we also explain the various methods to prepare the LPHNPs with various desired characteristics. Finally, the various therapeutic and clinical applications have been presented briefly.